Process and apparatus for preparing toner particles

ABSTRACT

Disclosed is an apparatus for obtaining toner particles with improved dispersion of additive components therein comprised of a toner extrusion device containing therein a blending chamber, a screw mixing means, a heating means, a toner supply means, and a means for injecting the additive components into the extrusion device enabling a decrease in the melting temperature of the toner resin particles contained therein.

This is a division of application Ser. No. 630,797, filed Jul. 13, 1984,now U.S. Pat. No. 4,973,439.

BACKGROUND OF THE INVENTION

This invention is generally directed to an apparatus and process for thepreparation of toner particles, and more specifically the presentinvention is directed to a continuous economical process for thepreparation of toner particles wherein there is effected a liquidinjection into the toner components during processing thereof, enablingan increase in the viscosity of the toner polymer, in view of thelowering of the melt temperature thereby permitting a more desirabledispersing of the pigment particles therein.

In one embodiment of the present invention, there is provided acontinuous process for the preparation of toner particles wherein thereis injected into the polymer components selected a liquid with a boilingpoint below the melt temperature of the toner composition, whereby theliquid vaporizes enabling the absorption of heat generated by theshearing of the polymer melt and thereby desirably lowering the melttemperature of the toner resin particles. Liquid injection is effectedin one specific embodiment with a specially designed nozzle means,however other means of injection can be used, which means areappropriately situated in a toner extrusion apparatus. This apparatusallows the continuous automatic control of toner processing parametersincluding the degree of dispersion of the pigment particles in the tonerresin particles. With the selection of such an extrusion apparatus theproperties of the toner composition can be determined during theprocessing thereof eliminating the need for sampling the tonersubsequent to its complete preparation, which sampling is usuallyaccomplished with each batch of toner being prepared. A suitableextrusion apparatus and process is described in a copending applicationU.S. Ser. No. 535,517/83, now abandoned, entitled "Apparatus and Processfor Controlling Toner Properties", the disclosure of this applicationbeing totally incorporated herein by reference.

Numerous devices and processes are known for effecting the preparationof toner particles. Examples of commercially known processes include themelt blending of the toner components in a Banbury apparatus. Othermethods include spray drying, dispersion polymerization, solutionpolymerization, and the like. Also it is known that toner compositionscan be obtained with an extrusion apparatus. An extrusion apparatus andprocess enables a number of advantages not achievable with the Banburyprocess in that, for example, extrusion is a continuous rather thanbatch operation and, the extrusion process is more susceptible toautomation, allowing more economical operation.

Moreover, it is known that water injection processes may be used for thepurpose of removing undesirable volatile components during theprocessing of polymer compositions. However, there is no teaching inthis prior art as to the concept of selecting liquid injection for thepurpose of controlling, for example, the melt temperature of the polymercomponents needed for obtaining toner compositions, and wherein thereresults improved pigment dispersion. The prior art is silent withrespect to processing toner compositions with a liquid injection means.

Toner compositions selected for causing the development of images inelectrostatic imaging systems must be of the proper triboelectric chargein order to achieve high quality developed images of suitableresolution. The triboelectric charge is primarily effected by the degreeof dispersion of the pigment particles and/or charge enchancingadditives incorporated therein. Dispersion of the pigment particles andinternal charging additives is directly dependent on the magnitude ofthe shear stress and the temperature history of the polymer componentsduring the melt mixing processes. Accordingly in most situations areduction in the polymer melt temperature generates higher stressenabling a more favorable dispersion therein of the pigment particlesand the charge enhancing additives. However, in many of the apparatusesand processes described herein for obtaining toner particles, such asthe Banbury roll mill, the compounding extruder, and the continuousmixing apparatus, the surface area required for heat transfer to reducethe melt temperature is severly limited.

Thus there remains a need for processes and apparatus for the continuouspreparation of toner compositions wherein there can be effected areduction in the melt temperature of the toner components. Moreover,there remains a need for a simple, economical extrusion toner processingapparatus wherein the melting temperature of the polymer components canbe desirably lowered by a liquid injection process. Further, therecontinues to be a need for enabling the liquid injection of componentsinto the toner compositions being prepared, and wherein this injectioncan be effected in a continuous manner during the extrusion process.Moreover, there remains a need for a continuous process and apparatuswhich will enable increased dispersion of pigment particles, and/orcharge enhancing additives into the toner composition components,thereby desirably effecting the resulting triboelectric charge containedon the toner resin particles. Additionally, there continues to be a needfor an apparatus and process wherein liquid injection of water,suspensions with pigment particles, and charge enhancing additives, orsolution mixtures having incorporated therein charge enhancingadditives, can be accomplished in a continuous manner, and wherein theproperties of the toner compositions produced may be continuouslymonitored during processing that is, on line, enabling the necessaryadjustments to the equipment to be effected immediately andautomatically. Furthermore, there continues to be a need for a processand apparatus which will enable a simple, economical method forcontinuously monitoring and maintaining the capacitance and conductancevalues of toner components selected for preparing the tonercompositions, and wherein during toner processing there can be injectedby a nozzle various components into a toner composition causing themelting temperature thereof to be desirably reduced. Also, therecontinues to be a need for an apparatus and process which continuouslyand accurately measures the capacitance, or the amount of pigmentparticles contained in the toner resin selected, and the conductance,that is the degree of dispersion of the pigment particles in the tonerresin particles, which measurements are desirably accomplished on lineenabling the automatic adjustment of various processing parameters inorder that toner particles of desired properties can be obtained.Additionally, there continues to be a need for the preparation of tonerparticles by extrusion processes, wherein there is injected variouscomponents into the polymer resinous particles, and where tonercompositions can be prepared in a continuous manner rather than inbatches as is effected with the known Banbury roll mixers, whichextrusion apparatus contains as an integral part thereof, a nozzleinjecting means, and an optional sensing device. Moreover, there remainsa need for a process and apparatus wherein there can be injected into atoner composition aqueous solutions, a suspension containing thereincarbon black particles, or charge enhancing additives, a solution havingdissolved therein charge enhancing additives, waxes, and the like,desirably enabling the lowering of the melt temperature of the tonercomposition, and causing the viscosity of the polymer contained thereinto increase.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a continuous processand apparatus which overcomes many of the above-noted disadvantages.

It is yet another object of the present invention to provide a processand apparatus for effecting the continuous injection of variouscomponents in a toner composition containing, for example, toner resinparticles, and pigment particles.

In another object of the present invention there is provided acontinuous process, and apparatus for injecting various components,including charge enhancing additives, and pigment particles, into atoner composition during processing thereof, especially extrusionprocessing.

In still another object of the present invention there is provided aprocess and apparatus for measuring on line the capacitance andconductive properties of a composition comprised of polymeric resinousparticles and pigment particles, and wherein there is selected a nozzlefor injecting various components therein, enabling the lowering of themelt temperature of the toner polymer components.

In a further object of the present invention there is provided a processand apparatus for effecting the injection of aqueous solutions into atoner composition during processing thereof causing a decrease in themelt temperature of this composition.

In yet another object of the present invention there is provided acontinuous process and apparatus for the injection of solutions withcarbon black particles or charge enhancing additives, suspensions havingincorporated therein carbon black particles or charge enhancingadditives, waxes, and similar materials, into a toner composition duringprocessing thereof, particularly extrusion processing, causing alowering of the melt temperature of the composition, thereby allowingthe pigment particles or charge enhancing additives to be moreeffectively dispersed in the toner components.

In yet another object of the present invention there is provided anextrusion process and an extrusion apparatus, wherein there is effecteda continuous liquid injection of various components into the tonercomposition, enabling the resulting toner particles to possess desiredtriboelectric properties, improved dispersion of pigment particles andcharge enhancing additives therein, controlled admixing characteristics,and desirable charge distribution, these compositions being useful forcausing the development of images in electrostatographic and printingdevices.

These and other objects of the present invention are accomplished byproviding a process and apparatus for effecting the injection of variouscomponents into a toner composition formulation enabling the lowering ofthe melt temperature thereof. More specifically, in accordance with oneembodiment of the present invention, there is provided a continuousprocess and apparatus, with an injection means for introducing variouscomponents into the toner composition processed in the apparatus,enabling the lowering of the polymer melt temperature, and allowingpigment particles, charge enhancing particles, and the like to beeffectively dispersed therein.

In one specific embodiment the present invention is directed to anapparatus for obtaining toner particles having desirably dispersedtherein pigment particles, comprising providing a toner processingapparatus, including continuous compounding devices such as extrusionsystems, and a means for injecting into the apparatus various componentscausing a decrease in the melting temperature of the toner polymercomposition present in the apparatus. A toner extrusion device that canbe selected is described in the copending application mentionedhereinbefore, the disclosure of which is totally incorporated herein byreference. This device is generally comprised of a blending chamber, ascrew mixing means, a heating means, a toner supply means, and a sensingdevice with two electrodes which generate AC signals for measuring thecapacitance and conductance values of the components passingtherebetween subsequent to mixing in the extrusion blending chamber. Inaccordance with the process described in the copending application,there is provided an extrusion device followed by adding theretocomponents of toner resin particles and pigment particles. A sensinghead which is an integral part of the extrusion device is comprised oftwo electrodes. Actuating the electrodes causes an electrical signal tobe directed to the toner components. These signals are then directed toa capacitance conductance bridge, and subsequently to a microprocessorand a computer control device in operative relationship with theextrusion apparatus allowing for the automatic on line modifications asappropriate of the extrusion apparatus parameters, thereby resulting intoner particles of desired properties.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention and further featuresthereof, reference is made to the following detailed description ofvarious preferred embodiments wherein:

FIG. 1 is a partially schematic cross-sectional view of a tonerextrusion apparatus with an injection means; and

FIG. 2 illustrates in detail a specific nozzle device selected forinjection.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Illustrated in FIG. 1 is a twin screw extrusion device 1, containing adrive motor means 3, a gear reducer means 5, a belt means 7, a blendingchamber 9, a screw means 11, a supply means or hopper 13, with tonerresin particles, and pigment particles 14 therein, a thermocouple means15, a heating means 17, a die or head pressure means 19, an optionalsensing head 21, electrodes 23, and lead wires 24, which are connectedto a capacitance or conductance type bridge, an injection means 27, anda vacuum extractor 29. In operation the components to be extruded, forexample toner resin particles, and pigment particles, enter theextrusion apparatus from the toner supply means 13. These components areblended and thoroughly mixed in chamber 9 by rotation of screw 11. Thisblending is usually accomplished at elevated temperatures contolled byheating means 17. Subsequent to a suitable effective mixing period theresulting product is directed to the sensing head, and more specificallyis caused to pass between the electrodes 23, having applied thereto analternating current (AC) signal for the primary purpose of measuring theconductance and capacitance values thereof of the product. Thisinformation is then generated to other components situated in closeproximity to the extrusion apparatus, reference FIG. 2 of the referredto copending application for the purpose of translating the signal intouseful information which is interpreted by a computer, automaticallyproviding for adjustments to the toner extrusion process parameters.During extrusion processing there is introduced into the tonerformulation subsequent to melting thereof, various components, by theinjecting means 27, enabling a reduction in the melt temperature of thetoner composition, causing an increase in the viscosity thereof, and thedesirable dispersion of pigment particles, for example, therein. Thisincreased dispersion of pigment particles enables a toner compositionwith various desirable properties including acceptable triboelectriccharging values, controlled admix characteristics, suitable chargedistribution properties, and the like.

With further reference to FIG. 1 the speed of the screw 11 can be of anysuitable value providing the objectives of the present invention areachieved. Generally, however, the speed of screw 11 in one embodiment isfrom about 100 revolutions per minute to about 250 revolutions perminute. The temperature in the blending chamber 9 can vary, however,generally this temperature, which is controlled by a thermocouple 15 andgenerated by heating means 17, is from about 50 degrees centigrade toabout 120 degrees centigrade. The die or head pressure 19 generatespressure of from about 200 pounds per square inch to about 1,500 poundsper square inch. In one embodiment the screw is allowed to rotate at 200revolutions per minute, the temperature in the chamber 11 is maintainedat 100 degrees centigrade, and the die or head pressure is 200 poundsper square inch.

Parameters associated with the blending chamber, including the amount ofpolymer resin particles and pigment particles introduced therein can becontrolled by means of a computer which receives information from amicroprocessor on a continuous basis. The microprocessor is operativelyconnected to a capacitance, conductance bridge which transmitsinformation to the microprocessor based on data generated from thesensing head 21 connected to the bridge by wires 24. Alternatively, atoner processing device, such as the extrusion apparatus shown in FIG.1, need not contain a sensing means therein, nor a computer arrangement,rather the process parameters can be adjusted, if appropriate, bysampling the toner composition product obtained subsequent to processingas is commonly affected, for example, with the Banbury mill mixingapparatus.

Illustrated in FIG. 2 is a specific nozzle means 27 for injectingvarious components into the toner processing apparatus, which means issuitably anchored to the processing apparatus, and is comprised of avalve 43, a screw adjuster 45, a valve needle 47, seals or O rings 49, anozzle component 51, operative conduits 53, air pressure gauge 55, airpump means 56, air pressure valve 57 for controlling the flow of airinto the nozzle, valve 61 for controlling the flow of components intothe nozzle, and pump 63 for introducing the components into the nozzle.In operation, the pump 63 introduces at a suitable pressure controlledby gauge 59, components, such as water, that flow through conduit 53,and are injected into the toner formulation by nozzle 51, and morespecifically by needle 47. Pressurized air is introduced into the systemfor the purpose of preventing needle 47 from clogging. This air isgenerally not simultaneously introduced with the liquid, rather thevalve 61 is closed prior to introducing air into the nozzle chamber.

The injection means, such as the injecting nozzle of FIG. 2 can besituated at various locations in the toner processing apparatus,providing that the objectives of the present invention are achievable,however, generally the injecting means is located at a position thatwill allow sufficient time for the toner polymer to achieve melting. Inone illustrative embodiment the nozzle is located at a distance on theextrusion apparatus of from about 6 times the diameter to about 8 timesthe diameter of the screw device. Moreover, there can be selected amultiple number of injecting means, thus more than one nozzle can belocated in the toner processing apparatus, and suitably effectivelyspaced from the first nozzle. For example, with regard to the extrusiondevice as illustrated in FIG. 1, and assuming a screw length of 8 feet,two nozzles can be positioned and secured thereto with a distancetherebetween of about 4 feet.

The injecting means, which is operatively connected to the extrusionapparatus as illustrated, enables the efficient controlled introductionof various components into the toner formulation. These components areinjected in the form of a solution enabling the melt temperature of thetoner composition to be desirably lowered subsequent to vacuumextraction of vapors with means 29. Generally, the melt temperature ofthe toner polymer component is reduced 10° F. for each 1 percent ofsolution component injected therein. More specifically, the melttemperature of the toner polymer component which can initially be fromabout 330° F. to about 350° F. may be lowered to about 280° F.subsequent to the injection therein of a 5 percent water solutioncontaining charge enhancing additives therein. This lowering of themelting temperature enables a more effective dispersion of the pigmentparticles present in the toner formulation, and increased dispersion ofthe charge enhancing additives. The lower melting temperature is causedby evaporation of the components injected into the extrusion device,these components having a lower boiling point than the meltingtemperature of the toner components. In this manner, upon evaporationand extraction with means 29, heat is extracted from the toner meltcausing the temperature to be significantly decreased.

Examples of materials that can be selected for injection into the tonerprocessing apparatus include those components which generally have aboiling point lower than the melt temperature of the polymer components.Accordingly, in one embodiment of the present invention, substances witha boiling point of from about 50° F. to about 240° F., and preferablyfrom about 80° F. to about 220° F. can be used. Thus, various solutionsor solution mixtures of components can be injected into the tonerformulation. Illustrative examples of these components include water,solution mixtures having present therein pigment particles such ascarbon black, solution mixtures having dissolved therein chargeenhancing additives, suspension mixtures containing therein pigmentparticles, suspension mixtures with charge enhancing additives, waxes,and the like. With further reference to the components, the solventselected for the solution mixture can be comprised of any substance thatwill affectively dissolve or form dispersions of the pigment particlesor charge enhancing additive components present therein. Thesesubstances include, for example, water, aliphatic alcohols, such asmethanol and ethanol, and the like. Examples of suspension mediumsinclude those substances which will not effect the dissolution of thepigment particles or charge enhancing additives, illustrative examplesof which are organic solvents such as chloroform.

While the components can be introduced into the toner processingapparatus at various selected suitable amounts, providing the objectivesof the present invention are achieved, in one embodiment for every 100pounds per hour of toner formulation processed there is injected thereinfrom about 5 pounds to about 10 pounds of liquid. Thus, for example, asolution mixture comprised of from about 20 percent by weight to about30 percent by weight of charge enhancing additives is injected into theextrusion device of FIG. 1 at an effective rate, generally of from about1 to about 10 pounds and preferably from about 3 pounds to about 7.5pounds per hour.

In one specific sequence of operation there is introduced into theblending chamber of the device of FIG. 1, a toner composition comprisedof a copolymer of styrene and n-butyl methacrylate, comprised of 58percent by weight of styrene and 42 percent by weight of n-butylmethacrylate; or a styrene butadiene resin copolymer, 89 percent byweight of styrene, and 11 percent by weight of butadiene; and 10 percentby weight of carbon black particles. Subsequent to melting of the tonerpolymer there is introduced therein by the injection nozzle 27, amixture of water and 3 percent by weight of cetyl pyridinium chloride.Evaporation of the water and extraction of the resulting vapors byvacuum extraction means 29 causes the toner polymer component mixturetemperature to be lowered in view of the loss of heat therefrom.Accordingly, in this embodiment, the melt temperature of the tonerpolymer component in the extrusion apparatus is lowered about 60° F.,that is from 350° F. to 290° F., enabling the carbon black particles tobe pulverized, and thus more effectively dispersed into the polymerparticles. Additionally, the charge enhancing additive is also moreeffectively dispersed therein.

During the blending operation as accomplished by the rotation of screw11, the molten toner composition resulting is caused to flow between apair of electrodes situated in the sensing device whereby the materialis subjected to an AC signal. The response signal is read by acapacitance, conductance bridge, which converts such a reading tocapacitance and conductance numbers. This data in turn is submitted to amicroprocessor and control computer wherein equipment processingadjustments, as appropriate, can be accomplished for the extrudingapparatus.

The relationship of the percentage of pigment particles, such as carbonblack, or charge enhancing additives, present in the toner resinparticles as a function of the capacitance and conductance values duringextrusion, is as illustrated in the referred to copending application.For example, a conductance value of 2 nano mhos at a capacitance of 20picofarads indicates that 10 percent of carbon black particles have beenproperly dispersed in the toner mixture. Improper dispersion of thepigment particles in the toner resin particles, as is well known, canadversely effect the rate at which toner particles acquire charge, thetriboelectric charging values, copy quality, and image resolution.Additionally, undesirable background appears on developed images whereinthe carbon black particles, for example, are not uniformly and properlydispersed in the polymer resin particles. The degree of dispersion ofpigment particles and charge enhancing additives in the toner resinparticles can be determined by known methods, including ASTM designationD2663.

Examples of suitable toner resin selected for processing in accordancewith the present invention include polyimides, epoxies, diolefins,polyurethanes, vinyl resins and polymeric esterification products of adicarboxylic acid and a diol comprising a diphenol. Any suitable vinylresin may be selected for the toner resins of the present applicationincluding homopolymers or copolymers of two or more vinyl monomers.Typical of such vinyl monomeric units include: styrene, p-chlorostyrene,vinyl naphthalene, unsaturated mono-olefins such as ethylene, propylene,butylene, and isobutylene; vinyl halides such as vinyl chloride, vinylbromide, vinyl fluoride, vinyl acetate, vinyl propionate, vinylbenzoate, vinyl butyrate and the like; vinyl esters such as esters ofmonocarboxylic acids including methyl acrylate, ethyl acrylate,n-butylacrylate, isobutyl acrylate, dodecyl acrylate, n-octyl acrylate,2-chloroethyl acrylate, phenyl acrylate, methylalpha-chloroacrylate,methyl methacrylate, ethyl methacrylate, and butyl methacrylate;acrylonitrile, methacrylonitrile, acrylimide; vinyl ethers, such asvinyl methyl ether, vinyl isobutyl ether, vinyl ethyl ether, and thelike; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone,methyl isopropenyl ketone and the like; vinylidene halides such asvinylidene chloride, vinylidene chlorofluoride and the like; and N-vinylindole, N-vinyl pyrrolidene and the like; styrene butadiene copolymers,and mixtures thereof.

Various suitable pigment particles can be selected including carbonblack, magnetites which consist of a mixture of magnetic oxides,inclusive of the commercially available Mapico blacks, nigrosine dyes,colored pigments such as cyan, magenta, yellow, blue, green, and thelike. These pigment particles are present in the toner composition in anamount of from about 3 percent by weight to about 20 percent by weight.When the pigment particles are comprised of magnetites, they are presentin the toner composition in the amount of from about 10 percent byweight to about 70 percent by weight, and preferably in an amount offrom about 20 percent by weight to about 50 percent by weight.

Illustrative examples of magenta materials that may be selected forincorporation into the toner composition include, for example,2,9-dimethyl-substituted quinacridone, an anthraquinone dye identifiedin the color index as Cl 60710; Cl Dispersed Red 15, a diazo dyeidentified in the color index as Cl 26050; Cl Solvent Red 19, and thelike. Illustrative examples of cyan materials that may be used aspigments include copper tetra 4(octadecyl sulfonamido) phthalocyanine;X-copper phthalocyanine pigment listed in the color index as Cl 74160;Cl Pigment Blue; Anthrathrene Blue, identified in the color index as Cl69810; and Special Blue X-2137. Examples of yellow pigments that may beselected include diarylide yellow 3,3-dichlorobenzideneacetoacetanilides, a monoazo pigment identified in the color index as Cl12700, Cl Solvent Yellow 16; a nitrophenyl amine sulfonimide identifiedin the color index as Foron yellow SE/GLN, Cl dispersed yellow 33;2,5-dimethoxy-4-sulfonanilide phenylazo-4'-chloro-2,5-dimethoxyaceto-acetanilide, permanent yellow FGL, and other similar yellows. Thepigments of cyan, magenta, and yellow, when used with the chargeenhancing additives, are generally present in the toner composition inan amount of from about 2 weight percent to about 15 weight percentbased on the weight of the toner resin particles.

Various known suitable effective charge enhancing additives can beselected for incorporation into the toner compositions of the presentinvention such as quaternary ammonium compounds; alkyl pyridiniumcompounds, reference U.S. Pat. No. 4,298,672, the disclosure of which istotally incorporated herein by reference; organic sulfate and sulfonatecompositions, U.S. Pat. No. 4,338,390, the disclosure of which istotally incorporated herein by reference; cetyl pyridiniumtetrafluoroborates; and the like. These charge enhancing additives areintroduced into the toner formulation by the injecting means, and areusually present in the final toner composition in an amount of fromabout 1 percent by weight to about 20 percent by weight.

Illustrative examples of wax components that can be introduced into thetoner formulation are preferably comprised of low molecular weightmaterials, inclusive of those with a molecular weight of from about1,000 to about 20,000, including polyethylenes, and polypropylenes.

Thereafter the resulting toner composition can be formulated into adeveloper composition by mixing with carrier particles. Illustrativeexamples of carrier particles that can be selected for mixing with thetoner composition prepared in accordance with the present inventioninclude those particles that are capable of triboelectrically obtaininga charge of opposite polarity to that of the toner particles.Accordingly, in one embodiment the carrier particles are selected so asto be of a negative polarity in order that the toner particles which arepositively charged will adhere to and surround the carrier particles.Illustrative examples of such carrier particles include granular zircon,granular silicon, glass, steel, nickel, iron ferrites, silicon dioxide,and the like. Additionally, there can be selected as carrier particlesnickel berry carriers as disclosed in U.S. Pat. No. 3,847,604, thedisclosure of which is totally incorporated herein by reference,comprised of nodular carrier beads of nickel, characterized by surfacesof reoccurring recesses and protrusions thereby providing particles witha relatively large external area.

The selected carrier particles can be used with or without a coating,the coating generally being comprised of fluoropolymers, such aspolyvinylidenefluoride resins; terpolymers of styrene;methylmethacrylate; a silane, such as triethoxy silane;tetrafluoroethylenes; other know coatings and the like.

The diameter of the carrier particles is generally from about 50 micronsto about 1,000 microns, thus allowing these particles to possesssufficient density and inertia to avoid adherance to the electrostaticimages during the development process. The carrier particles can bemixed with the toner particles in various suitable combinations,however, best results are obtained when about 1 part per toner to about10 parts to about 200 parts by weight of carrier are mixed.

Examples of toner processing apparatus include continuous compoundingdevices, such as single screw extruders, and twin screw extruders,continuous mixers, transfer mixers, co-kneaders, and the like, withextrusion apparatuses being preferred.

While it is not desired to be limited by theory, it is believed that adecrease in the melt temperature of the toner composition causes theviscosity of the polymer component to increase significantly, resultingin higher shear, and thus enabling more effective dispersion of thecarbon particles or charge enhancing additive components. Morespecifically, the shear forces cause pulverization of the carbon blackparticles, for example, to submicron sizes, less than 3 microns enablingbetter dispersion thereof. As a result, there is obtained tonerparticles with controlled admix characteristics, stable triboelectriccharging values and good charge distribution characteristics. Thus, atoner composition prepared in accordance with the process of the presentinvention possesses an admix charging rate of less than 5 minutes, ascompared to an undesirable admix charging rate of about 15 minutes for atoner composition which does not have injected therein a water solutionin accordance with the process described herein.

Although the invention has been described with reference to specificpreferred embodiments, it is not intended to be limited thereto, ratherthose skilled in the art will recognize that variations andmodifications may be made therein which are within the spirit of thepresent invention and within the scope of the following claims.

What is claimed is:
 1. An apparatus for obtaining toner particles withimproved dispersion of additive components comprised in operativerelationship of a toner extrusion device with an exit means positionedopposite the entrance means of said toner extrusion device containingtherein a blending chamber, a screw mixing means, a heating means, atoner supply means positioned externally to the extrusion device, ameans for injecting liquid components into the extrusion device attachedto the extrusion device, and a sensing means comprised of two electrodesenabling the measurement of the capacitance and conductance values ofsaid components passing therebetween, and subsequent to injection of thecomponents therein, said sensing means with two electrodes beingattached to the exit of the extrusion device.
 2. An apparatus inaccordance with claim 1, wherein the injecting means is a nozzle.
 3. Anapparatus in accordance with claim 1, wherein the injecting means iscomprised of multiple nozzles.
 4. An apparatus in accordance with claim1, wherein said extrusion device is a twin screw extruder.
 5. Anapparatus in accordance with claim 1, wherein there is further includedtherein a capacitance, conductance bridge which receives signalsgenerated from a sensing head located on the sensing means; and convertsthese signals into data directed to a microprocessor, and a computercontrol device wherein the computer device is programmed in a mannerenabling the control of the process parameters of the extrusionapparatus.
 6. An apparatus for obtaining toner particles with improveddispersion of additive components, which apparatus is comprised inoperative relationship of a twin screw extrusion device and connectedthereto a drive motor means, a gear reducer means, and a belt means witha blending chamber, and a screw means, therein said extrusion device, asupply means positioned externally to the extrusion device, which supplymeans contains therein toner resin particles and pigment particles, athermal couple means, a heating means, a die means, a sensing head, twoelectrodes, which electrodes are an operable connection with acapacitance or conductance type bridge, and wherein said sensing meanswith two electrodes is attached to the exit of said extrusion device, aninjecting means attached to the extrusion device for injecting liquidcomponents into the extrusion device, and a vacuum extractor attached tothe extrusion device whereby said resin particles and pigment particlesentering the extrusion apparatus from the toner supply means are blendedand thoroughly mixed in said chamber by rotation of said screws, saidblending being accomplished at elevated temperatures by said heatingmeans, and thereafter directing the resulting product to pass betweensaid electrodes which have applied thereto an alternating currentwhereby the conductance and capacitance values of said product aredetermined.